JP6901012B2 - Data acquisition method in mass spectrometer - Google Patents

Description

The present invention relates to the field of mass spectrometry (MS) data acquisition, and more particularly to novel data acquisition methods in mass spectrometers.

High-resolution tandem mass spectrometers are now an important analytical instrument in omics analysis (including metabolomics, proteomics, etc.). High-throughput, high-sensitivity, and high-coverage mass spectrometry data acquisition methods are required for composite samples in omics analysis. Conventional methods include the Data Dependent Acquisition Method (DDA) proposed by Ducret et al. In 1998. In this method, a precursor ion scan is first performed, then precursor ions having a large abundance are selected, and these are allowed to enter a collision cell to dissociate, thereby acquiring a product ion spectrum. This method is still a widely used acquisition method because it can achieve high coverage for the analysis target.

In recent years, data-independent acquisition methods (DIA) have been rapidly developed. Compared to the DDA method, this method has higher sensitivity, wider dynamic range, and higher analytical throughput and better quantification capacity. Such Typical representatives of such methods, there are a MS ^E method described in Patent Document 1, a SWATH method described in Patent Document 2. The MS ^E method, first performed precursor ion scan, then subjected to dissociation by supplying precursor ions in the collision cell extensive or overall mass window records the product ion spectrum. The precursor ion and the product ion are subjected to a deconvolution algorithm by utilizing the retention time and peak profile of the same target precursor ion and product ion in chromatography (or ion mobility mass spectrometry) having the same characteristics. Be associated. Since the SWATH method mainly targets target analysis, pre-scanning of precursor ions can be omitted. Normally, precursor ions are directly separated according to their mass, and the width of each window is, for example, 25 Da. Each window of the precursor ion selected by the quadrupole is then introduced into the collision cell for dissociation. The product ion spectrum is recorded here and compared to the database, after which the product ion intensity is used for quantification. In either method, precursor ions covering the entire range of the mass window are selected, introduced into the collision cell, and dissociated at the same time. However, there is a contradiction that if the mass window is too small, the efficiency of the DIA method will decrease, which means that the ion utilization efficiency will be too low and it will take time to scan the entire mass range. Is. Also, if the mass window is too large, the ion utilization efficiency will improve, but the spectral complexity will increase, and data post-processing (for example, identifying the analysis target by comparing with the database, or using precursor ions and product ions) will increase. The difficulty level of (performing deconvolution to correlate) will increase. For this reason, mismatches and erroneous determinations of the ions to be analyzed occur. Therefore, there is a need for a way to resolve the above issues or contradictions.

U.S. Pat. No. 6,717,130 U.S. Pat. No. 8,809,770 U.S. Pat. No. 5,672,870

In view of the above drawbacks in the prior art, an object of the present invention is to provide a data independent acquisition method in a mass spectrometer to solve the above problems in the prior art.

To achieve the above and other related objectives, the present invention a. A step of providing an ion source to generate precursor ions, and b. In the step of supplying the precursor ion to the first mass spectrometer, in the first mass spectrometer, the precursor ion located outside the mass window passes through the first mass spectrometer, and the said The step of selecting at least one mass window so that the precursor ion located in the mass window cannot pass through the first mass spectrometer, and c. The step of supplying the precursor ions passing through the first mass spectrometer to the collision cell to perform collision dissociation to generate product ions, and d. The step of supplying the product ion to the second mass spectrometer, performing mass spectrometry, and recording the spectrum, and e. A step in which steps b to d are repeated, and each time step b is repeated, the selected mass window includes a step that does not overlap with all the previously selected mass windows. Provided is a data acquisition method in a mass spectrometer in which the repetition is stopped after all the mass windows in the mass range are selected.

In one embodiment of the invention, the method further comprises step f following step e, where step f corresponds to said product ion produced by said precursor ion in the selected mass window. Includes obtaining the spectrum to be produced by primary data post-processing.

In one embodiment of the invention, the method further comprises step g or step j following step f. The step g comprises acquiring the spectrum corresponding to the product ion produced by the precursor ion in the selected mass window by a second mathematical post-treatment, the step j comprising said product. This includes comparing the spectrum of ions with a database to identify the analysis target.

In one embodiment of the invention, the method further comprises step h following step e, which includes obtaining the total spectrum by summing all the recorded spectra.

In one embodiment of the present invention, if step g is included after step f, step i is included after step h, and if step j is included after step f, step i'is included after step h. Will be included. The step i includes taking the spectrum acquired in step g as a qualitative result and taking the total spectrum obtained in step h as a quantitative result. The step i'includes performing a quantitative analysis based on a combination of the results obtained in step j and the total spectrum obtained in step h.

In one embodiment of the invention, the method further comprises step a followed by step k at least once, in which step K is the first mass spectrometer for all the ions in the mass range. Dissociation is performed by passing through the collision cell and entering the collision cell, and all the dissociated product ions are supplied to the second mass spectrometer to perform mass spectrometry and record a spectrum.

In one embodiment of the present invention, the mass spectrum acquired in step k is used as one of the data sources in step f to correct the calculation error in step f.

In one embodiment of the present invention, the spectrum is subjected to noise reduction processing before step f.

In one embodiment of the present invention, the noise reduction process includes removing high frequency noise by a fast Fourier transform algorithm.

In one embodiment of the present invention, the step of performing chromatographic separation of the analysis target is included before step a.

In one embodiment of the invention, the secondary data post-processing in step g is the same precursor of the analysis, depending on the consistency of the chromatographic peak profile or retention time between the precursor ion and the product ion. Includes performing deconvolution that correlates ions with product ions.

In one embodiment of the invention, a precursor ion scan is included prior to step b, and the scan is performed by the second mass spectrometer.

In one embodiment of the present invention, the first mass spectrometer is a quadrupole mass spectrometer, an ion trap mass spectrometer, or a time-of-flight mass spectrometer.

In one embodiment of the present invention, the second mass spectrometer is a time-of-flight mass spectrometer or a Fourier transform mass spectrometer.

In one embodiment of the present invention, a step of separating the precursor ions according to the ion mobility is included before step b.

In one embodiment of the invention, ions in the mass window that do not pass through the first mass spectrometer are released along a particular direction of the first mass spectrometer for subsequent analysis or detection. To.

In one embodiment of the invention, in step b, a mass window containing at least 5 mass units (Dalton) in succession is selected by the first mass spectrometer.

In one embodiment of the invention, in step b, at least five discontinuous mass windows are selected by the first mass spectrometer, each window comprising one mass unit (Dalton).

In one embodiment of the invention, the at least five discontinuous mass windows have a pseudo-random distribution.

In one embodiment of the invention, the inverse Hadamard transform algorithm is used in the primary data post-processing.

As described above, the mass spectrum data acquisition method of the present invention can realize extremely high ion utilization efficiency as compared with the prior art, and thus has excellent quantification ability. In addition, the difficulty of data post-processing can be significantly reduced, and the possibility of discrepancy or erroneous determination between the parent ion to be analyzed and the product ion is reduced. Therefore, the data acquisition method of the present invention has a strong identification ability.

It is the schematic which shows the apparatus in the prior art of this invention. It is the schematic which shows the apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows the method which concerns on 1st Embodiment of this invention. It is the schematic which shows the selection sequence of the mass window which concerns on 1st Embodiment of this invention. 5A to 5F show mass spectra before and after the primary data post-processing in one embodiment of the present invention. It is a flowchart which shows the method which concerns on 2nd Embodiment of this invention. It is a flowchart which partially shows the method which concerns on 3rd Embodiment of this invention.

The implementation of the present invention is described below with specific embodiments, and other advantages and effects of the present invention can be easily understood by those skilled in the art from the disclosed contents of the present invention. .. The present invention can be embodied or implemented in various other specific embodiments, and the details of the present specification can be similarly based on various viewpoints and uses, and the present invention. Various modifications and changes can be made without departing from the spirit and scope of. It should be noted that the following embodiments and the constituent requirements of the embodiments can be combined with each other without conflicting with each other.

It should be noted that the drawings shown in the following embodiments are merely schematic examples of the basic concept of the present invention, and thus only the components related to the present invention are shown in the drawings. Therefore, in actual implementation, these drawings are not necessarily drawn according to the number, shape, and size of the components. In practice, the format, number, and proportion of each component may change randomly, and the layout of these components may become more complex.

FIG. 1 is a schematic view showing an apparatus used in a DIA technology solution that is currently common, such as the SWATH method described in Patent Document 2 (not a schematic view showing an acquisition method). 1 is an ion source used for ion generation and transfer, 2 is a first mass spectrometer (eg, quadrupole) used for selecting precursor ions, and 3 is a precursor ion. A collision cell used when dissociating to generate product ions, and reference numeral 4 denotes a second mass spectrometer (usually a high-resolution mass spectrometer) for analyzing product ions. The specific analysis process is as follows. The ion 5 in the mass window M ₁ is selected by the first mass spectrometer 2, _{and the other ions 6 located outside the mass window M 1} cannot pass through the quadrupole 2 and are discarded. .. Normally, the width of the mass window M ₁ is several to several tens of mass units (Da) such as 20 Da, and all precursor ions having a width of 20 Da enter the collision cell 3 and dissociate due to collision, resulting in a large number of products. Ions are generated. All of these product ions enter the second mass spectrometer 4 to perform mass spectrometry, whereby the product ion spectrum is acquired. Then, in the first mass analyzer 2, the same window width, i.e., have a 20 Da, which the previously selected mass range is selected the mass window M ₂ which do not overlap, and collision-induced dissociation Following this The product ion spectrum is recorded. This process is repeated until the preset mass range is completely covered by the selected mass window. Since the above product ion spectrum is generated by precursor ions in the 20 Da range, post-processing of the data is required. Usually, two methods are feasible. One is a method of identifying the analysis target by directly comparing it with the database, and the other is the consistency of the chromatograph peak profile or retention time between the precursor ion and the product ion of the same analysis target. Correspondingly, it is a method of making precursor ions correspond to product ions by performing mathematical deconvolution processing, that is, obtaining a product ion spectrum corresponding to each precursor ion.

When a 20 Da mass window is used in a typical mass range such as 101 Da to 2100 Da m / z by the above method, 100 times of MS / MS analysis is required, that is, the ion utilization efficiency is 1%. A wider mass window, such as 200 Da, can be used to increase efficiency. In this case, only 10 MS / MS analyzes are required, and the ion utilization efficiency is 10%. However, all precursor ions in the 200 Da range enter the collision cell and dissociate, which produces a large number of product ions, which makes the product ion spectrum extremely complicated. In this case, it becomes very difficult to carry out data post-processing. It may not be possible to determine the product ion according to the database, or there may be numerous discrepancies between the precursor ion and the product ion.

With reference to 5F of FIGS. 2 to 5, the present invention provides a method of acquiring data in a mass spectrometer, which method comprises the following steps.

In step a, precursor ions are generated from the ion source 1'.

In step b, the mass window is split. As shown in FIG. 4, the sum of n _{windows, M 1, M 2, ...} , M i, ..., is divided into mass range including _{M n-1,} and _{M n.} For example, when the mass range is 101 Da to 2100 Da and the width of the mass window is 20 Da, 100 mass windows are M ₁ (101 to 120 Da), M ₂ (121 to 140 Da), M ₃ (141 to 160 Da) ... M. _It is represented as 99 (2061 to 2080 Da) and M ₁₀₀ (2081 to 2100 Da), respectively. Then, as shown in FIG. 2, the primary ion screening is performed by the first mass spectrometer 2'. Unlike the prior art, the ion filter of this embodiment, ions in the mass window M ₁ (numeral 5 in FIG. 2 'is shown in), the first mass analyzer 2' can not pass through a mass window All _{the ions located outside M 1 (that is, the ions of mass windows M 2 to} M ₁₀₀ having masses in the range of 121 Da to 2100 Da, represented by the number 6'in FIG. 2) are all the first mass spectrometers. Pass 2'.

In step c, all the passing ions (iones of _{mass windows M 2 to M 100} ) enter collision cell 3'and undergo collision-induced dissociation as shown in FIG. 2, thereby producing a large number of product ions. ..

In step d, all product ions enter the second mass spectrometer 4'as shown in FIG. 2 for mass spectrometry, and then the product ion spectrum is recorded. As shown in 5A of FIG. 5, the product ion spectrum is a complex spectrum having m / z on the horizontal axis and ion signal intensity on the vertical axis. Mathematically, the mass j ion signal intensity _{(S (1, j)} and display) that corresponds to the mass window _{M 1} a, mass j generated by the precursor ion in the respective windows _M 2 _{~M 100} product ion can be considered as the superposition of strength, when displaying a product ion intensity of mass j generated by the precursor ion in the window _{M i I (i, j) and, S (1, j) =} I (2, _j) + I _{(3, j)} + ... + I _{(99, j)} + I _{(100, j)} .

In step e, the process from b to d is repeated. However, in this case, the choice of window in step b unlike the, for example, window M ₂ is selected. That is, _{the ions located inside the window M 2} cannot pass through the mass spectrometer 2', and _{all the ions located outside the window M 2} pass through and dissociate due to collision. The product ion spectrum is then recorded, as shown in 5B of FIG. The process is M ₃ , M ₄ . .. .. ~ M ₁₀₀ are selected in sequence and repeated until all mass windows are selected, after which the step is stopped. FIG. 4 shows a mass window selection sequence. Note that this sequence does not have to be in ascending or descending order of m / z, and may be in any order.

上記の関係式から、以下の式を簡単に得ることができる。

ここで、ｉ＝１，２…１００であり、Ｉ_{（ｉ、ｊ）}は、ｉ番目のウインドウ内のプリカーサイオンによって生成される質量ｊのプロダクトイオンの強度である。このようにして、１００個全てのスペクトルを使用して、個々のウインドウ内のプリカーサイオンによって生成されるさらに１００個のプロダクトイオンスペクトルが取得される。１番目、２番目、およびｎ番目のスペクトルをそれぞれ図５の５Ｄ、５Ｅ、および５Ｆに示している。 In step f, the primary data post-processing is performed. In steps d and e, 100 product ion spectra were generated (first, second, and nth spectra are shown in 5A, 5B, and 5C, respectively, of FIG. 5), where each spectrum is shown. The result is the superposition of the spectra of the product ions produced by the precursor ions in 99 windows. This data post-processing is performed to obtain the spectrum of product ions produced by the precursor ions in the individual windows. If it is considered that there is no substantial change in the peak pattern of the precursor ions to be analyzed during the acquisition of 100 product ion spectra, the following relational expression holds.

From the above relational expression, the following equation can be easily obtained.

Here, i = 1, 2, ... 100, and I _{(i, j)} is the intensity of the product ion of mass j produced by the precursor ion in the i-th window. In this way, all 100 spectra are used to obtain an additional 100 product ion spectra produced by the precursor ions in the individual windows. The first, second, and nth spectra are shown in 5D, 5E, and 5F of FIG. 5, respectively.

In step g, secondary data post-processing is performed. The product ion spectrum obtained in step f is a spectrum of hybrid product ions generated by the collision of precursor ions in the mass range (ie, mass window). Although the mass window is not large (20 Da in the above embodiment), deconvolution is required to obtain the product ion spectrum corresponding to each precursor ion. Therefore, step g is consistent with most DIA deconvolution processes. The usual treatment method utilizes the consistency of chromatographic peak profiles or retention time information between precursor ions and product ions to perform mathematical deconvolution and the same analyzed precursor ions and products. Includes steps to correlate with ions. Common algorithms for deconvolution include Pearson's correlation coefficient, cross-correlation score, k-means clustering, entropy minimization, dot product score, and minimum spanning tree. Since various algorithms are well known to those skilled in the art, they will not be described here.

In step h, all the product ion spectra acquired in step d and step e are summed to obtain the total spectrum.

In step i, the results of steps g and h are combined and data analysis is performed. In this step, the result of step g is used for qualitative analysis. That is, the mass-to-charge ratio, isotope abundance distribution, fragment distribution, chromatography retention time, and other information of the high-resolution product ion spectrum, as well as information about the reference material in the preset database (of the standard material stored in the database). The ions to be analyzed are determined according to a combination of mass-to-charge ratio, retention time, isotope abundance ratio, and other information, and then this analysis is based on the product ion intensity information of the total spectrum obtained in step h. Quantify the target ion.

The above described in the present invention as compared to prior art (ie, as described in the background art, selectively passing through a mass window to record product ion spectra and performing data post-processing). In the step, a method of not selectively passing through the mass window is used, which greatly improves the ion utilization efficiency, and at that time, the smaller the window, the higher the ion utilization efficiency. For example, this mass window is 20 Da. In the 2000 Da mass range, the remaining ions in the 1980 Da mass range can pass through. In one cycle, the total ion utilization efficiency is 99%, which is 99 times the ion utilization efficiency in the method of selectively passing the ions. Such ion utilization efficiency is reflected in the extremely high product ionic strength of the total spectrum obtained in step h. Having high ion utilization efficiency guarantees the excellent quantification ability of this method. On the other hand, since the present invention tends to select a narrower mass window, preferably 10 to 30 Da, the complexity of the product ion spectrum obtained in step f is significantly reduced, and the subsequent mathematics of step g is performed. In a typical deconvolution process, the difficulty of deconvolution is greatly reduced. As a matter of course, the present invention separately provides a data post-processing process (step f) as compared with the prior art, but the difficulty of calculation and the consumption of calculation time in the process are extremely low.

In the above embodiment, after step a, the method causes all the ions in the mass range to pass through the first mass spectrometer, enters the collision cell to dissociate, and dissociates all the dissociated product ions in the second. This step k can be repeated a plurality of times, further including a step k of feeding the mass spectrometer to perform mass spectrometry and recording the spectrum. The spectrum in this case is actually a spectrum corresponding to the product ions produced by all the precursor ions, and is essentially the same as the total spectrum obtained in step h. However, the spectrum can be acquired multiple times within one chromatographic spot and can be used as one of the data sources in step f. By this step, the calculation error of step f due to the change of the chromatograph peak profile can be corrected.

In the above embodiment, a step of mathematical processing can be included before step f, and in this step, noise reduction processing is performed on the entire original mass spectrum. The reason for performing this step is that the method allows so many ions to pass that noise (mainly chemical noise, neutral noise, and noise due to solvent effects, etc.) should also be avoided from being recorded in the spectrum. Because it cannot be done. In order to obtain a signal-to-noise ratio higher than that of the conventional method, it is necessary to first perform noise reduction processing. A very efficient noise reduction step is to remove high frequency noise by fast Fourier transform. Here, high frequency noise is mainly generated by the influence of solvent molecules and ions in chromatography (mainly liquid chromatography).

In the above embodiment, the step of performing chromatographic separation is usually included before step a. Information about the separation of analytical objects by chromatography, such as the chromatographic peak profile and retention time, can be used as part of the data source for data post-processing performed in step g.

In the above embodiment, a precursor ion scanning process can be included before step b, which scanning process is performed by a second mass spectrometer. High resolution precursor ion spectra are typically required for use as part of a data source for data post-processing performed in step g.

In the above embodiment, the first mass spectrometer is preferably a quadrupole mass spectrometer, which can be used for other analysis such as an ion trap mass spectrometer and a time-of-flight mass spectrometer. It can also be a device. When using a quadrupole as a first mass spectrometer, the ions in the selected window are excited by bipolar RF or quadrupole RF to allow ions outside a particular mass window to pass through. It is excited so that the ions are emitted along the radial direction (or other direction) of the quadrupole, preventing it from moving to the next stage. A similar method is described in Patent Document 3. The second mass spectrometer is preferably a high-resolution mass spectrometer such as a time-of-flight mass spectrometer and a Fourier transform mass spectrometer.

In the above embodiment, the detector detects ions in the mass window that do not pass through the first mass spectrometer, such as ions selectively excited by a quadrupole or an ion trap and emitted radially. It can be done or left for further analysis.

In the above embodiment, a step of separating precursor ions according to the ion mobility can be included before step b. Information on the separation of analysis targets according to the ion mobility, such as the peak pattern of the ion mobility and the drift time, can be used as part of the data source for data post-processing performed in step g.

FIG. 6 shows a second embodiment of the present invention. In the present embodiment, step j is carried out by omitting step g, and here, data analysis is directly carried out on the product ion spectrum acquired in step f. This step is similar to the data processing step of the SWATH method and mainly corresponds to target analysis. That is, the product ion spectra and chromatographic information are compared with those in the database and analyzed to identify the analysis target, then referencing the total spectrum obtained in step h as shown in step i'of FIG. We are conducting a quantitative analysis.

FIG. 7 shows a third embodiment according to the present invention. In step b'of this embodiment, instead of selecting a single mass window, a plurality of mass windows (for example, five) are selected. These mass windows are preferably discontinuous, and each mass window contains only a unit mass (1 dalton). Furthermore, these mass windows have a pseudo-random distribution. Ions located outside the selected mass windows pass through the first mass spectrometer. At this time, the data post-processing in step f is an inverse Hadamard transform. Such algorithms with various uses are widely used in time-of-flight mass spectrometry, ion mobility spectroscopic analysis, and the like, and are well known to those skilled in the art, and are not described here. The advantage of this embodiment is that the signal-to-noise ratio of the converted data is significantly improved because the information of all product ion spectra is used in the conversion process, not just one spectrum. In the present embodiment, the first mass spectrometer is preferably an ion trap type mass spectrometer. By using such a mass spectrometer, ions of any selected mass can be easily released, thereby avoiding the supply of ions to the next collision cell. Further, the first mass spectrometer may be a quadrupole mass spectrometer. In the case of a quadrupole mass spectrometer, it is generally considered difficult to release ions in a Dalton mass window due to the rapid passage of ions, that is, the occurrence of only a low RF vibration period. However, it is now known that this purpose can be achieved by the technique of applying a special high-frequency electric field. Therefore, there are no restrictions on the quadrupole mass spectrometer in this embodiment.

In summary, the MS data acquisition method of the present invention improves the ion utilization efficiency in the data-independent acquisition method, reduces the difficulty of data post-processing, and effectively overcomes various drawbacks in the prior art. Therefore, it will have high industrial application value.

The above embodiments are merely exemplary of the principles and advantages of the invention and are not intended to limit the invention. One of ordinary skill in the art can modify or modify the above embodiments without departing from the spirit and scope of the invention. Accordingly, all equivalent modifications or modifications made by one of ordinary skill in the art without departing from the spirit and scope of the invention are covered by the appended claims.

Claims (16)

a. The step of providing an ion source to generate precursor ions,
b. In the step of supplying the precursor ion to the first mass spectrometer, in the first mass spectrometer, the precursor ion located outside the mass window passes through the first mass spectrometer, and the said A step of selecting at least one mass window so that the precursor ion located in the mass window cannot pass through the first mass spectrometer.
c. A step of supplying the precursor ion passing through the first mass spectrometer to a collision cell to perform collision dissociation to generate a product ion.
d. A step of supplying the product ion to the second mass spectrometer, performing mass spectrometry, and recording the product ion spectrum.
e. It is a step of repeating steps b to d until all the mass windows in the mass range are selected, and each time step b is repeatedly executed, the mass window selected is selected before that. with any mass window have overlapping products, and the step,
Step f after step e and
Step g or step j after step f ,
And step h to be after step e comprises <br/>,
Before Symbol step f comprises said generated by the precursor ion of a selected mass in the window, the first spectrum corresponding to the product ions to acquire the primary data post-processing,
The step g comprises obtaining a second spectrum corresponding to the product ion produced by the precursor ion in the selected mass window by a second mathematical post-treatment.
Step j, the product ion compares Nsu spectrum to a database, look including the identification of the analyte,
The step h includes obtaining the total spectrum by summing all the recorded product ion spectra.
If step g is included after step f, step i is included after step h, and if step j is included after step f, step i'is included after step h.
The step i includes taking the second spectrum acquired in step g as a qualitative result and the total spectrum obtained in step h as a quantitative result.
Step i 'is based on a combination of the total spectrum obtained in step h to the results obtained in step j, the data acquisition method in including, mass spectrometer to perform quantitative analysis. After step a, a step of performing step k at least once is included.
In step k, all the precursor ions in the mass range are passed through the first mass spectrometer to enter the collision cell for dissociation, and all the dissociated product ions are subjected to the second mass. The data acquisition method according to claim 1 , further comprising supplying to an analyzer, performing mass spectrometry, and recording a mass spectrum. The data acquisition method according to claim 2 , wherein the mass spectrum acquired in step k is used as one of the data sources in step f to correct the calculation error in step f. The data acquisition method according to claim 1 , wherein noise reduction processing is performed on the product ion spectrum before step f. The data acquisition method according to claim 4 , wherein the noise reduction processing includes removing high-frequency noise by a fast Fourier transform algorithm. The data acquisition method according to claim 1, wherein the step of performing chromatographic separation of the analysis target is included before step a. The secondary data post-processing in step g correlates the precursor ions of the same analysis with the product ions, depending on the consistency of the chromatographic peak profile or retention time between the precursor ions and the product ions. The data acquisition method according to claim 6 , which comprises carrying out deconvolution. The data acquisition method according to claim 1, wherein a precursor ion scan is included before step b, and the scan is performed by the second mass spectrometer. The data acquisition method according to claim 1, wherein the first mass spectrometer is a quadrupole mass spectrometer, an ion trap mass spectrometer, or a time-of-flight mass spectrometer. The data acquisition method according to claim 1, wherein the second mass spectrometer is a time-of-flight mass spectrometer or a Fourier transform mass spectrometer. The data acquisition method according to claim 1, further comprising a step of separating the precursor ions according to the ion mobility before step b. The first aspect of claim 1, wherein the ions in the mass window that do not pass through the first mass spectrometer are released along a particular direction of the first mass spectrometer for subsequent analysis or detection. Data acquisition method. The data acquisition method according to any one of claims 1 to 12 , wherein in step b, a mass window containing at least 5 mass units (Dalton) continuously is selected by the first mass spectrometer. The invention according to any one of claims 1 to 12 , wherein in step b, at least five discontinuous mass windows are selected by the first mass spectrometer, and each window comprises one mass unit (Dalton). Data acquisition method. The data acquisition method according to claim 14 , wherein the at least five discontinuous mass windows form a pseudo-random distribution. The data acquisition method according to claim 15 , wherein in step f, the algorithm of the inverse Hadamard transform is used in the primary data post-processing.

Images